The present invention relates to an in-line powder bulk density measuring instrument.
In a manufacturing process powder bulk density is conventionally monitored by tapping a sample of the product stream under standardized conditions and calculating the ratio of mass to volume from the observed results. The conventional measurement techniques are reasonably accurate for particular samples, but they leave much to be desired in view of the hiatus between the time the sample is obtained from the product stream and the time the density is determined. During this time, which may be on the order of ten minutes in the manufacture of powdered tea, product continues to be made, possibly with the wrong bulk density.
Ideally, bulk density should be measured in zero time. In the past, this could not be achieved because the physical process involved in compacting a powder to its "tapped density" or minimum volume state inherently involves time.
The problem of measuring "tapped density" involves the measurement of mass, the definition of volume, and the establishment of well-defined energy-time input conditions.